The present invention relates to an image rendering apparatus, a head up display, and an image luminance adjusting method.
Laser scanning image display apparatuses that project and display images on screens by scanning laser beams two-dimensionally are well known (e.g., Japanese Unexamined Patent Application Publication No. 2010-139687). The laser scanning image display apparatuses are used for Head Up Displays (HUDs), projectors, and the like that project and display images on windshields and combiners, etc., of automobiles. In the laser scanning image display apparatus, laser beams are reflected by an MEMS mirror, an orientation of which is changed horizontally and vertically, to thereby scan the laser beams.
An image display apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2010-139687 changes an amount of light from a laser light source when a gobo shields light from an MEMS mirror in such a way that an amount of light accumulated in a predetermined period will be constant. This enables the amount of light absorbed into the MEMS mirror in the predetermined period to be maintained constant even when a luminance of an image is drastically reduced. Thus, a fluctuation in a resonance frequency of the MEMS mirror can be reduced, thereby achieving stable operations.